"Joerg" wrote in message
...
When researching upgrades to larger rotors I read that there may be limits
for frames and forks. Why?

Explanations were usually scant and contradictory, with some saying it
doesn't matter and some saying it does. After all, when increasing the
rotor diameter by a couple of inches the brake force on the caliper goes
down by about 30% and then due to it being positioned farther out this
should cantilever back into the same +30% into the frame or fork bosses as
before. The maximum deceleration achievable on each wheel remains the
same, until it is very close to locking up. So it should be a wash,
shouldn't it?

Bicycle brake rotors are pretty thin and fragile - the bigger you make it;
the more vulnerable it is.